Binary Ag—Cu amorphous thin-films for electronic applications

ABSTRACT

An interconnect and a method of making an interconnect between one or more features on a substrate comprises: sputtering a noble metal-copper eutectic thin film under controlled power on an oxide grown or deposited on a substrate; and forming an amorphous alloy structure from the noble metal-copper eutectic thin film in the shape of the interconnect and the interconnect comprising no grain or grain boundaries without temperature sensitive resistivity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to U.S. Provisional PatentApplication Ser. No. 62/374,209 filed on Aug. 12, 2016, the entirecontents of which are incorporated herein by reference.

STATEMENT OF FEDERALLY FUNDED RESEARCH

None.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of interconnects,and more particularly, to interconnect lines in semiconductor devices.

BACKGROUND OF THE INVENTION

Without limiting the scope of the invention, its background is describedin connection with metallic thin film materials.

Recently, low resistive, highly durable metallic thin film materials areunder vigorous search in order to develop the sub-20 nm scaleinterconnects for integrated circuits (ICs) and electrode development[1]. The sharp rise in resistivity in conventional metallic thin films(i.e. Cu, Al) with the scaling down of interconnect width in ICs hasbecome a key challenge for the semiconductor industry [2]. This abruptlowering of electrical properties are due to the presence of grain andgrain boundaries and surface scattering in polycrystalline thin filmsbelow sub-20 nm scale. Electron scattering at the grain boundaries alsogenerates unusual heat, which reduces the lifetime of interconnects andaffect their reliability [1,3,4]. Therefore, obtaining a thin/conformaldiffusion barrier has become increasingly difficult in narrow metallictrench lines. Similarly, when feature size of the nano-scale conductorsshrink, the electro-migration (i.e. flow of materials and segregationowing to the high current density) effect dominates, thus, diminishesthe durability and the reliability of devices [5]. Although, carbonnanotubes and graphene have been explored as potential candidates forfuture interconnect materials, the significant challenges are tointegrate them with existing silicon technology.

Noble metals and their alloys exhibit low resistivity, high thermalconductivity, good adhesion and good electro-migration resistance. Amongthem, silver (Ag) is one of the materials exhibit lowest resistivitywith very high electro-migration resistance owing to its higher Z value[6]. On the other hand, Cu is widely used to interconnect materials insemiconductor industry due to its high electrical and thermalconductivity and low cost. However, Cu based nanoscale interconnectsexhibit serious reliability issues, thus, limits its application belowsub-20 nm scale owing to its low electro-migration resistance [7].

Recently, it has been shown that microwave processed Ag—Cupolycrystalline thin film exhibits the lowest resistivity and goodelectro-migration resistance [5]. Mishra et. al demonstrate the additionof Al in Ag could possibly improve the electro-migration resistance ofthe Ag, which further helps in large-scale integration of the circuitry[8]. However, all these proposed techniques are based on thepolycrystalline thin films where major electron transport is inhibitedby the defect-planes, such as, grain-boundaries (GBs) and barrierinterfaces (BIs). When the dimension of the metals/alloys interconnectfall below the mean-free path of the electron the increase inresistivity only occurs due to the defect scattering. Few recent reportsreveal that the GBs itself in nano-scale exhibit extremely highresistivity, which suppress the electron conduction by several order ofmagnitude [4,9]. In addition, it has been shown that the addition of Cuin single crystal Ag enhances the electrical conductivity of Ag singlecrystal thin film [10]. Nevertheless, the employment of nanoscale singlecrystal conductor has so far proven unrealistic.

SUMMARY OF THE INVENTION

In one embodiment, the present invention includes a method of making aninterconnect between one or more features on a substrate comprising:growing or depositing a thermal oxide on a substrate; sputtering a noblemetal-copper metallic glass thin film under controlled power on thethermal oxide; and forming the noble metal-copper metallic glass thinfilm into the interconnect. In one aspect, the noble metal is selectedfrom at least one of ruthenium, rhodium, palladium, silver, osmium,iridium, platinum, or gold. In another aspect, the sputtering stepfurther comprises using a temperature gradient assist. In anotheraspect, the noble metal-copper metallic glass thin film is a eutecticthat comprises between 20, 30, 40, 50, 60, and 70 atomic % (at %) noblemetal and the remainder Cu. In another aspect, the noble metal-coppermetallic glass thin film is a eutectic that comprises between 20, 30,40, 50, 60, and 70 at % Cu and the remainder the noble metal. In anotheraspect, the deposition rate of the sputtering step is 0.5, 0.6, 0.7,0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 Å/s.In another aspect, the controlled power is defined further as a lowpower sputtering at about 20, 30, 40, 50, 60, 70, 80 or 90 watts. Inanother aspect, the controlled power is a low power sputtering using aDC magnetron. In another aspect, a base pressure and a depositionpressure during the sputtering step is between ˜10−7 Torr and ˜10−3Torr. In another aspect, a temperature of the substrate temperature ismaintained at about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,or 25° C. In another aspect, the substrate is a silicon substrate. Inanother aspect, the interconnect shows little to no change inresistivity in a temperature range of 77K to 340K. In another aspect, aresistivity of the Au or Ag-copper eutectic thin film is generallyindependent of temperature.

Another embodiment of the present invention includes a method of makingan interconnect between one or more features on a substrate comprising:sputtering an Au or Ag-copper eutectic thin film under controlled poweron an oxide grown or deposited on a substrate; and forming an amorphousalloy structure from the Au or Ag-copper eutectic thin film in the shapeof the interconnect and the interconnect comprising no grain or grainboundaries without temperature sensitive resistivity. In one aspect, aresistivity of the Au or Ag-copper eutectic thin film is generallyindependent of temperature.

Yet another embodiment of the present invention includes an integratedcircuit interconnect on a substrate comprising: an amorphous metallicalloy thin eutectic film disposed on the substrate, wherein the metallicalloy comprises a noble metal-copper thin film and is homogenous with nopoly-crystalline heterogeneity. In one aspect, the noble metal isselected from at least one of ruthenium, rhodium, palladium, silver,osmium, iridium, platinum, or gold. In another aspect, the sputteringstep further comprises using a temperature gradient assist. In anotheraspect, the noble metal-copper metallic glass thin film is a eutecticthat comprises between 20, 30, 40, 50, 60, and 70 at % noble metal andthe remainder Cu. In another aspect, the noble metal-copper metallicglass thin film is a eutectic that comprises between 20, 30, 40, 50, 60,and 70 at % Cu and the remainder the noble metal. In another aspect, theinterconnect is formed with a deposition rate of 0.5, 0.6, 0.7, 0.8,0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 Å/s. Inanother aspect, the interconnect is formed by a low power sputtering atabout 20, 30, 40, 50, 60, 70, 80 or 90 watts. In another aspect, theinterconnect is formed by sputtering with a DC magnetron. In anotheraspect, the interconnect is formed with a base pressure and a depositionpressure of between ˜10−7 Torr and ˜10−3 Torr during sputtering. Inanother aspect, a temperature of the substrate temperature is maintainedat about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25° C.In another aspect, the substrate is a silicon substrate. In anotheraspect, the interconnect shows little to no change in resistivity in atemperature range of 77K to 340K. In another aspect, a resistivity ofthe Au or Ag-copper eutectic thin film is generally independent oftemperature. In another aspect, the interconnect comprises at least oneof: a high surface tension and an anatomically smooth surface or smallline edge roughness, produces a uniform electric field across theinterconnect, comprises no grain, and/or comprises no grain boundaries.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the features and advantages of thepresent invention, reference is now made to the detailed description ofthe invention along with the accompanying figures and in which:

FIGS. 1A and 1B are schematics showing: in FIG. 1A the state-of-the-artmetallic polycrystalline Cu thin films with grain-boundary and electronscattering; and in FIG. 1B the microstructure of Ag—Cu metallic glassthin film with a grain boundary free structure of the present invention.

FIGS. 2A and 2B show high-resolution transmission electron micrograph(HRTEM) and shows the complete amorphous structure of the thin film (Nograin and grain boundaries are found in the microstructure). Selectedarea diffraction (SAD) pattern (inset of FIG. 2B) shows the diffusestructure, which is a stereotypical characteristic of amorphousmaterials.

FIG. 3 is a graph of low angle XRD pattern showing the amorphousstructure of the 10 nm Ag—Cu thin-films.

FIGS. 4A and 4B show graphs of X-ray Photo electron spectroscopy ofAg—Cu thin film showing characteristic Cu2p3 (FIG. 4A) and Ag3d (FIG.4B) peaks.

FIG. 5A is a graph that shows the current-voltage characteristics of 10nm Ag—Cu thin films showing the metallic behavior of the film; and FIG.5B is a graph that shows the temperature dependent resistivity of the 10nm Ag—Cu thin film.

FIGS. 6A and 6B are graphs of ultraviolet photo-emission (UPS) spectraof 10 nm Ag—Cu metallic glass thin films showing (FIG. 6A) valance bandat He—I excitation (21.2 EV); and (FIG. 6B) the secondary electroncutoff of the thin film.

FIG. 7 is a process flow chart of method of making an interconnectbetween one or more features on a substrate in accordance with oneembodiment of the present invention.

FIG. 8 is a process flow chart of method of making an interconnectbetween one or more features on a substrate in accordance with anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatcan be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

There is a sharp increase in resistivity of metallic thin films with thereduction of film thickness. This is attributed to increased grainboundary and surface scattering in polycrystalline metallic thin films.The present inventors have synthesized a noble metal-copper (e.g., aAg—Cu (composition close to 60 at % Ag-40 at % Cu)) thin film that isfully amorphous by DC magnetron sputtering. The metallic thin films ofthe present invention show extraordinarily high conductivity, very smalltemperature dependence of resistivity, and have the potential ofreplacing crystalline metals in several thin-film electronicapplications, including deeply scaled interconnects large-scaleintegrated circuits. The amorphous metallic alloy thin films of thepresent invention can be used in a number of integrated circuit featuresas an interconnect and/or as a wire. For example, the invention may findparticular uses for: low dimension high conducting films formicro-electro-mechanical systems (MEMS); highly conductive thin films;and/or as an excellent material for giant magneto-resistance. Theinvention can also be used to overcome a variety of technologicalchallenges, including: the exponential increase in resistivity of lowdimensional thin films for semiconductor field effect transistordevices; as a low loss conductor for electrical switching applications;in devices requiring high electrical conductivity with low heatgeneration; and/or to overcome voltage drop issues in field-emissiondevices due to heterogeneous interfaces.

What is needed are new devices and methods that provide ultra-lowresistivity, good thermal conductivity, low electro-migration, andexcellent adhesion with the substrate. The present inventors havedeveloped amorphous metallic alloy thin films that overcome many of theissues associated with poly-crystalline metallic thin films. The reasonsfor choosing a metallic glassy system include: (i) homogeneousshort-range structure with no poly-crystalline heterogeneity, (ii) GBsand BIs free structure, (iii) extraordinary mechanical strength (youngmodulus, hardness, and friction properties), and (iv) highcorrosion/erosion resistance. More specifically, metallic-glasses havehigh quality factor because of low internal friction in amorphousstructure and absence of dislocation based energy dissipation. Due tothese unique characteristics, metallic glasses thin film are one of thepotentially transformative future materials in interconnects andnano-scale electrode applications. Since inert nature of surfacestructure, metallic glasses could be unique as it prevail the effect ofsuccessive changes in the ambience, which is indeed rare in the othernano-scale conductors [11]. In this context, binary amorphous alloystructure are attractive due to the following reasons: (i) homogeneousmetalloid-free structure (ii) alloy composition is ICs fabricationcompatible [12], and (iii) GB/BI free isotropic structure contain lowerscattering points. In one non-limiting example, the present inventorsshow making a Ag—Cu binary eutectic (60.12 atomic % (at %) Ag-39.88 at %Cu) alloy is one of the potential material where Ag and Cu both exhibitlowest resistivity and integrated circuit (IC) fabrication compatible.The inventors demonstrate herein the formation of amorphous sub-20 nmAg—Cu alloy thin film with high electrical conductivity. The presentinvention shows that the electrical conductivity of Ag—Cu alloy belongsto the level between pure Ag and pure Cu and is independent oftemperature. The homogeneous isotropic structure with high conductivityis further explained using their valance band study in ultra-violetphotoemission spectroscopy (UPS).

Metallic-glasses (MG) overcome many of the problems associated withpoly-crystalline copper. FIG. 1A shows a state-of-the-art metallicpolycrystalline Cu thin films, however these metallic polycrystalline Cuthin films include significant grain-boundary and electron scattering.FIG. 1B shows the microstructure of Ag—Cu metallic glass thin film witha grain boundary free structure of the present invention. As theschematic in FIG. 1B shows (and the images of FIGS. 2A and 2B), thereare no grain boundary scattering losses in metallic-glasses of thepresent invention due to their amorphous nature because they arehomogeneous and isotropic down to atomic scale.

The present inventors deposited an Ag—Cu thin film using low power DCmagnetron sputtering of thickness 10 nm±2.5 nm on a ultra-clean thermaloxide coated Si substrate. The deposition power was kept at ˜50 watts inorder to control the deposition rate (˜1.33 Å/s) and the substratetemperature was maintained ˜16° C. The low power and slow depositionrate along with a sufficient temperature gradient assists in formationof the amorphous alloy structure from the Ag—Cu eutectic composition(60.12 at % Ag-39.88 at % Cu). Similarly, a 99.999% pure Ag and Cu thinfilm was deposited in a similar fashion in order to achieve acomparative study. The base pressure and the deposition pressure of thesputtering unit were kept at ˜10 ⁻⁷ Torr and 10⁻³ Torr, respectively.

FIG. 2A shows the high resolution transmission electron microscopy(HRTEM) image of the 10 nm thin film demonstrating the completeamorphous structure with no grain and grain boundaries. A clear absenceof grain and grain-boundaries in the nano-structure validates thesuccessful deposition of Ag—Cu amorphous thin film on the ambientcondition. FIG. 2B shows the defect structure of the film using theselected area diffraction (SAD) pattern taken inside of the TEM. The SADpattern shows the diffuse electron diffraction pattern, which furthermanifest the complete amorphous nature of the Cu—Ag thin film.

FIG. 3 demonstrates the small angle XRD pattern collected inside ofX-ray diffraction instrument (Bruker, USA) from angle 20° to 66°. Thepattern demonstrates the stereotypical broad hump representation of theamorphous structure of the Cu—Ag thin film. The x-ray photoelectronspectroscopy (XPS) was performed using a PHI 5000 Versaprobe x-rayphotoelectron spectrometer in order to investigate the surfacecharacteristics/surface composition of the as deposited thin film.

FIG. 4A and FIG. 4B show the characteristic Ag 3d_(5/2) and Cu 2p_(3/2)peak positions at 932.48 eV and 368.31 eV, respectively [13]. Thesurface composition of the film was calculated after correcting thebaseline of the XPS peak, optimizing the peak area, and fitting of thoseCu and Ag peaks using the Multipack software inbuilt with thespectrophotometer instrument. A surface composition of Ag 60.1 at %-Cu39.7% was obtained, and others <0.2% of the amorphous thin film, whichis very close to the targeted composition of the material to beachieved. Thus, the measure the surface homogeneity of Cu—Ag thin filmwas obtained, which was further confirmed after the data recorded in themultiple areas of the thin film. After analyzing all the data we observethe following: (1) All the characteristic peaks of Cu (2p_(3/2)) andSilver (3d_(5/2)) is same (shape, full-width half maxima FWHM, peakarea, intensity, etc.) at different surface positions; (2) there weresmall shift found in some of the peak positions; and (3) The surfacecomposition of the film was found almost close to the composition of ourstaring material. The tiny shift in peak positions of Cu and Ag islikely due to the stress developed in the amorphous alloy film duringsputtering.

The room temperature electrical properties of the thin films weremeasured using a Hall measurement system (Ecopia HMS 5000) and theresistivity and the conductivity values are calculated by averaging thetwenty (20) data points measured under exactly same condition. The roomtemperature (298K±2K) resistivity and the conductivity values of theamorphous Ag—Cu thin film was found to be 2.97×10⁶±4.92×10⁻⁹ (Ohm-cm)and 3.49×10⁵±5584.52 (Ohm-cm)⁻¹, respectively. The room temperatureresistivity of 99.999% Ag and 99.999% Cu thin film shows1.29×10⁻⁶±5.54×10⁻⁹ and 2.05×10⁻⁵±7.39×10⁻⁷ Ohm-cm, respectively. Thisobservation depicts that the resistivity of Ag—Cu thin film exhibit inbetween the resistivity of pure Ag and pure Cu. The temperature was keptconstant by using an inbuilt heater system with the substrate holder,which can be able to control the temperature fluctuation of ±0.1° C.Similarly, the electrical properties as a function of temperature wasalso measured using the same system from 77 K (−196° C.) to 340 K (67°C.) for each of the thin films as shown in FIG. 5A and FIG. 5B.

FIG. 5A shows the plot of resistivity as a function of temperature for99.999% Ag, 99.999% Cu and 99.999% Ag—Cu amorphous alloy thin films. Forpure Ag and pure Cu thin film the inventors found a substantial changesin resistivity, which are few orders of magnitude. However, no orderchange is observed for the resistivity for Ag—Cu thin film during theentire temperature range from 77 K (−196° C.) to 340 K (67° C.) and thetotal change in resistivity was found <17% (or 0.68 Ohm-cm) due to thechange in temperature from 77 K (−196° C.) to 340 K (67° C.). Thesefurther suggest a weak temperature dependence of resistivity foramorphous Ag—Cu alloy thin film, whereas pure polycrystalline Ag and Cuexhibit strong temperature dependence of resistivity as shown in FIG.5B. FIG. 5B shows a comparative log-log plot of resistivity vstemperature for all the three thin films altogether and the slope of thecurve depicts the change in resistivity due to the thermal vibration.Although the thermal vibrations are active for polycrystalline thinfilms, however, the effect of temperature is minimal or almostnegligible for the amorphous thin film.

The valance band study and work-function of all the thin film sampleswere carried out by ultraviolet photo-electron spectroscopy (UPS)inbuilt with a PHI 5000 Versaprobe UPS/XPS spectrometer usingHe—Iα=21.22 eV UV light, which was used to probe the valence bandstructure as well. The Work Function of the film is calculated accordingto the equation: Φ=hv−ΔE and found to be 4.2 eV for 10 nm Ag—Cuamorphous alloy thin film. FIG. 6A and FIG. 6B show the valance bandstructure of the 99.999% Ag, 99.999% Cu and 99.999% Ag—Cu amorphous thinfilm, respectively, at He—Iα (21.2 eV) excitation. All the spectra arecombined and plotted together in order to identify the electronicstructure and density of states (DOS) of the amorphous alloy, which iscoming from the elemental contribution of the each elements (as shown inFIG. 6A). FIG. 6A shows the broad UPS-valance band peaks for both99.999% Cu (Electron configuration: [Ar] 3d¹⁰ 4s¹) and 99.999% Ag(Electron configuration: [Kr] 4d¹⁰ 5s¹). The position and FWHM of the Cuand Ag peak indicate their effective density of state (DOS) of the Cu-3dband and Ag-4d band, respectively [14]. Similarly, the Ag—Cu amorphousalloy also exhibit the signature of both the d-bands of Cu and Ag intheir respective position. The DOS of Ag—Cu alloy can be identified as acomposite valance structure (the curve in FIG. 6A) of their individuald-bands as clearly indicated in FIG. 6A [14]. Thus, this furtherdemonstrates that the valance band structure of the amorphous alloy isconsists of the elemental DOS of the individual components [15].However, both the elemental Cu and Ag d-bands became broader (increaseof their FWHM) after these two elements form an amorphous alloy of Ag—Cucompared to their respective pure elemental forms [16]. The broaderd-band peaks reflect the overlapping exchange interaction between twodistinct elements (e.g. Ag and Cu in this case), which essentiallysuggest the homogeneous formation of Ag—Cu bonds compared to the Ag—Agand Cu—Cu bonds (One Ag atom has more Cu atoms as nearest neighborrather Ag atoms and vice-versa) [17]. This causes the widening of d bandDOS in the alloy compared to their individual d-band, which iscomparatively narrower. Hence, this homogeneous mixture creates adiscrete conduction level in the conduction band of alloy, whichimproves the conductivity of the 10 nm amorphous film.

Thus, the present invention includes, at least: (1) making a fullyamorphous film of the composition Cu—Ag (composition close to 60 at %Ag-40 at % Cu) has never been reported before; (2) making a fullyamorphous film by keeping the surface composition of Cu—Ag (compositionclose to 60 at % Ag-40 at % Cu); (3) the deposition of amorphous thinfilms on SiO₂/Si substrate; (4) the deposition of amorphous thin filmson SiO₂/Si substrate with different thickness by controlling power; (5)thickness optimization of the amorphous thin film by controlling thedeposition time; (6) the electrical resistivity of the thin films is inthe order of ˜10⁻⁷ Ohm-cm; (7) the valence band structure of the thinfilms; (8) the temperature dependence of the thin film is almostnegligible; and/or (9) the Magneto-resistance of the thin film is in theorder of ˜10³ Ohm.

While potentially less desirable, the following may be substituted forthe sputtering step: rapid cooling of bulk materials of the samecomposition; and/or fabrication of a thin wire <10 nm.

The following features and properties of invention demonstrate itsimprovement over prior methods or features: The improved featuresinclude: (a) the composition of the thin film; (b) the amorphous, grain,and grain-boundary free structure; and/or (c) the extraordinaryelectrical and mechanical properties.

Some of the improved properties include: high electrical conductivity,low electrical resistivity, high magneto-resistance, low temperaturedependence of resistivity/conductivity, low temperature dependence ofmagneto-resistance, good mechanical properties, good thermal properties,good corrosion resistance, and good ambient oxidation resistance.

In one specific non-limiting example, the present invention includes oneor more of the following features or steps: a composition close to Cu:40 atomic %; Ag: 60 atomic %, a rate of sputtering deposition: 1.43 Å/s,a vacuum chamber pressure (Base Pressure): 5×10−8 Torr, a depositionpressure: 15.8 mT (±1 mT), an applied power: 50 W, under a noble-gas,e.g., Argon.

Another improvement of the present invention overcomes the problemcaused when a metal conductor scales down to less than about 20nanometers, in which the resistivity increases dramatically due to grainboundary and surface scattering. Similarly, when temperature changes,the resistivity of those existing conductor materials also changesrapidly, resulting in unusual current flow, reliability issues, and thefailure of the devices. The thin film of the present invention has avery low resistivity at the 10 nm scale. In addition, the temperaturedependent resistivity of this new material is almost negligible in thetemperature range of 77K (−196° C.) to 340 K (67° C.).

FIG. 7 is a process flow chart of method 700 of making an interconnectbetween one or more features on a substrate in accordance with oneembodiment of the present invention. A thermal oxides is grown ordeposited on the substrate in block 702. A noble metal-copper metallicglass thin film is sputtered under controlled power on the thermal oxidein block 704. The noble metal-copper metallic glass thin film is formedinto the interconnect in block 706. In one aspect, the noble metal isselected from at least one of ruthenium, rhodium, palladium, silver,osmium, iridium, platinum, or gold. In another aspect, the sputteringstep further comprises using a temperature gradient assist. In anotheraspect, the noble metal-copper metallic glass thin film is a eutecticthat comprises between 20, 30, 40, 50, 60, and 70 atomic % (at %) noblemetal and the remainder Cu. In another aspect, the noble metal-coppermetallic glass thin film is a eutectic that comprises between 20, 30,40, 50, 60, and 70 at % Cu and the remainder the noble metal. In anotheraspect, the deposition rate of the sputtering step is 0.5, 0.6, 0.7,0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 Å/s.In another aspect, the controlled power is defined further as a lowpower sputtering at about 20, 30, 40, 50, 60, 70, 80 or 90 watts. Inanother aspect, the controlled power is a low power sputtering using aDC magnetron. In another aspect, a base pressure and a depositionpressure during the sputtering step is between ˜10−7 Torr and ˜10−3Torr. In another aspect, a temperature of the substrate temperature ismaintained at about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,or 25° C. In another aspect, the substrate is a silicon substrate. Inanother aspect, the interconnect shows little to no change inresistivity in a temperature range of 77K to 340K. In another aspect, aresistivity of the Au or Ag-copper eutectic thin film is generallyindependent of temperature.

FIG. 8 is a process flow chart of method 800 of making an interconnectbetween one or more features on a substrate in accordance with anotherembodiment of the present invention. An Au or Ag-copper eutectic thinfilm is sputtered under controlled power on an oxide grown or depositedon a substrate in block 802. An amorphous alloy structure is formed fromthe Au or Ag-copper eutectic thin film in the shape of the interconnectand the interconnect comprising no grain or grain boundaries withouttemperature sensitive resistivity in block 802. In one aspect, aresistivity of the Au or Ag-copper eutectic thin film is generallyindependent of temperature.

It is contemplated that any embodiment discussed in this specificationcan be implemented with respect to any method, kit, reagent, orcomposition of the invention, and vice versa. Furthermore, compositionsof the invention can be used to achieve methods of the invention.

It will be understood that particular embodiments described herein areshown by way of illustration and not as limitations of the invention.The principal features of this invention can be employed in variousembodiments without departing from the scope of the invention. Thoseskilled in the art will recognize, or be able to ascertain using no morethan routine experimentation, numerous equivalents to the specificprocedures described herein. Such equivalents are considered to bewithin the scope of this invention and are covered by the claims.

All publications and patent applications mentioned in the specificationare indicative of the level of skill of those skilled in the art towhich this invention pertains. All publications and patent applicationsare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

The use of the word “a” or “an” when used in conjunction with the term“comprising” in the claims and/or the specification may mean “one,” butit is also consistent with the meaning of “one or more,” “at least one,”and “one or more than one.” The use of the term “or” in the claims isused to mean “and/or” unless explicitly indicated to refer toalternatives only or the alternatives are mutually exclusive, althoughthe disclosure supports a definition that refers to only alternativesand “and/or.” Throughout this application, the term “about” is used toindicate that a value includes the inherent variation of error for thedevice, the method being employed to determine the value, or thevariation that exists among the study subjects.

As used in this specification and claim(s), the words “comprising” (andany form of comprising, such as “comprise” and “comprises”), “having”(and any form of having, such as “have” and “has”), “including” (and anyform of including, such as “includes” and “include”) or “containing”(and any form of containing, such as “contains” and “contain”) areinclusive or open-ended and do not exclude additional, unrecitedelements or method steps. In embodiments of any of the compositions andmethods provided herein, “comprising” may be replaced with “consistingessentially of” or “consisting of”. As used herein, the phrase“consisting essentially of” requires the specified integer(s) or stepsas well as those that do not materially affect the character or functionof the claimed invention. As used herein, the term “consisting” is usedto indicate the presence of the recited integer (e.g., a feature, anelement, a characteristic, a property, a method/process step or alimitation) or group of integers (e.g., feature(s), element(s),characteristic(s), propertie(s), method/process steps or limitation(s))only.

The term “or combinations thereof” as used herein refers to allpermutations and combinations of the listed items preceding the term.For example, “A, B, C, or combinations thereof” is intended to includeat least one of: A, B, C, AB, AC, BC, or ABC, and if order is importantin a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB.Continuing with this example, expressly included are combinations thatcontain repeats of one or more item or term, such as BB, AAA, AB, BBC,AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan willunderstand that typically there is no limit on the number of items orterms in any combination, unless otherwise apparent from the context.

As used herein, words of approximation such as, without limitation,“about”, “substantial” or “substantially” refers to a condition thatwhen so modified is understood to not necessarily be absolute or perfectbut would be considered close enough to those of ordinary skill in theart to warrant designating the condition as being present. The extent towhich the description may vary will depend on how great a change can beinstituted and still have one of ordinary skilled in the art recognizethe modified feature as still having the required characteristics andcapabilities of the unmodified feature. In general, but subject to thepreceding discussion, a numerical value herein that is modified by aword of approximation such as “about” may vary from the stated value byat least ±1, 2, 3, 4, 5, 6, 7, 10, 12 or 15%.

All of the compositions and/or methods disclosed and claimed herein canbe made and executed without undue experimentation in light of thepresent disclosure. While the compositions and methods of this inventionhave been described in terms of preferred embodiments, it will beapparent to those of skill in the art that variations may be applied tothe compositions and/or methods and in the steps or in the sequence ofsteps of the method described herein without departing from the concept,spirit and scope of the invention. All such similar substitutes andmodifications apparent to those skilled in the art are deemed to bewithin the spirit, scope and concept of the invention as defined by theappended claims.

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What is claimed is:
 1. A method of making an interconnect between one ormore features on a substrate comprising: growing or depositing a thermaloxide on the substrate; sputtering a noble metal-copper metallic alloyglass thin film under controlled power on the thermal oxide, wherein thenoble metal-copper metallic alloy glass thin film comprises 20 to 70 at% copper and a remainder at % noble metal; and forming the noblemetal-copper metallic alloy glass thin film into the interconnect,wherein the noble metal-copper metallic alloy glass thin film isamorphous.
 2. The method of claim 1, wherein the noble metal is selectedfrom at least one of ruthenium, rhodium, palladium, silver, osmium,iridium, platinum, or gold.
 3. The method of claim 1, further comprisingusing a temperature gradient assist during the sputtering.
 4. The methodof claim 1, wherein the noble metal-copper metallic alloy glass thinfilm is a eutectic that comprises between 60 to 80 at % noble metal anda remainder at % copper.
 5. The method of claim 1, wherein the noblemetal-copper metallic alloy glass thin film is a eutectic.
 6. The methodof claim 1, further comprising using a deposition rate of 0.5, 0.6, 0.7,0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 Å/sduring the sputtering.
 7. The method of claim 1, wherein the controlledpower is defined further as a low power sputtering at about 20, 30, 40,50, 60, 70, 80 or 90 watts.
 8. The method of claim 1, wherein thesputtering is performed using a DC magnetron.
 9. The method of claim 1,further comprising using a base pressure and a deposition pressurebetween ˜10⁻⁷ Torr and ˜10⁻³ Torr during the sputtering.
 10. The methodof claim 1, further comprising maintaining a temperature of thesubstrate at about 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,or 25° C.
 11. The method of claim 1, wherein the substrate is a siliconsubstrate.
 12. The method of claim 1, wherein the interconnect showslittle to no change in resistivity in a temperature range of 77K to340K.
 13. The method of claim 1, wherein a resistivity of the noblemetal-copper metallic alloy glass thin film is generally independent oftemperature.
 14. A method of making an interconnect between one or morefeatures on a substrate comprising: sputtering an Au or Ag-coppereutectic thin film under controlled power on an oxide grown or depositedon the substrate, wherein the Au or Ag-copper eutectic thin filmcomprises 20 to 70 at % copper and a remainder at % Au or Ag; andforming an amorphous alloy structure from the Au or Ag-copper eutecticthin film in the shape of the interconnect and the interconnectcomprising no grain or grain boundaries without temperature sensitiveresistivity.
 15. The method of claim 14, wherein a resistivity of the Auor Ag-copper eutectic thin film is generally independent of temperature.